Add snapshot name validation
Add snapshot name validation

And fill out the docs a bit more.

Signed-off-by: Joe Grund <06d81316378f5e1e8ce132d1348b3633ffa33f28@whamcloud.io>

intel-hpdd/intel-manager-for-lustre,intel-hpdd/intel-manager-for-lustre,intel-hpdd/intel-manager-for-lustre